The lattice stability and phonon response of Ti3C2Tx MXene at high pressure are important for understanding its mechanical and thermal properties fully. Here, we use in situ high hydrostatic pressure X-ray diffraction (XRD) and Raman spectroscopy to study the lattice deformation and phonon behavior of Ti3C2Tx MXene. XRD spectra indicate that no phase transformation occurs up to the pressure of 26.7GPa. The elastic constant along a lattice parameter was calculated to be 378GPa. In the Raman spectra obtained at high-pressure, the out-of-plane phonon modes (A(1g) at similar to 210, similar to 504, and similar to 711cm(-1)) exhibit monotonic blueshifts with increasing pressure. The Gruneisen parameters of these three modes were calculated to be 1.08, 1.16, and 0.29, respectively. These results enrich the basic property data of Ti3C2Tx MXene and would benefit the further understanding of this novel material.